That question’d be best answered by telling you the schema. The tables (and some example data) are as follows:

• feeds – id, name (“Jon”), url, blog_url, last_updated_at (when it was last scraped, for prioritisation), is_trusted (basically dictates whether to use tag whitelisting or blacklisting – if people start putting malicious Flash applets into their feeds to try to XSS abnib, or something, I’ll mark them untrusted and stop them – also, if they persistently just fill the thing with YouTube videos)
• users – id, username, password_hashed (SHA1 with a salt), feed_id (for associating user accounts with feeds, for a future feature), cookie (for remembering that you’re logged in)
• articles – (contains cached copies of downloaded articles – faster than parsing XML every page load) id, feed_id, guid, title, date, created_at, content, url, deleted_at (for things which no longer appear on the feed but are still in the cache), looks_like_delicious (for filtering out Jon and Bryn’s del.icio.us combined feeds – later, there’ll be an option to show these if you prefer)

Hope that answers your questions.